Trouble alarm for telegraph systems



June 19, 192s. 1,67%,830

M. K l RKWOOD TROUBLE ALARM FOR TELEGRAPH SYSTEMS Filed July 9, 1926 Stader/u L@ /Zvpal'atm' /7/a/mruus iii Patented June 19, 1928.

en A51TMS i iiiiictniiiait KIRK-woon, or

rowaoo; New `:En'lisier Assjielnoa fro" aimaient: TELE- PHONEAND rarnGaArH COMPANY, ir eonr'eaarion FNEW'YORK.

Tnon'nnn" ALARM non.

Appiicanoirflied: Jury 9,

My invention relates to' carrier telegraph systems, andv more particularly to arrangements for automatically producing an alarml when the circuitsio a system bccoineseriously unstable.

Among' the variousv forms of trouble ound inptelegraph circuits used for printer service is bias inthe receivedV signals,that is, the durational excessA off theA markingim- 'pulses over rthe yspacing impulses or vice versa. in voice frequency andv lhigh tre qiiency carrier telegraph systems it has been found that the bias ot all the channels ot a system is affected in a similar manner by such troubles as improper repeater gain.

It is the object of my invention to furnish automatic arrangements tor producing. an alarm to indicate to an attendant that the bias of the channels ot' a carrier syste-in is seriously great. Means tor producing such an alarm are especially valuable in connection with the maintenance ot satisfactory service on long carrier circuits during the night period, since when the bias exceeds a given amount, the circuits affected must be withdrawn from service for re-adjustment. y

The method and means ot' my invention will be clearly understood when the following description is r-ead with reterenceto the accompanying drawing, showing diagramniatically, and in part schematically, three telegraph circuits forming a carrier system, one ot the circuits being arranged for use in producing the desired trouble alarm.

Three telegraph circuits are shown connecting station A and station B. The upper two circuits, including lines L, and L2, respectively, are designed for telegraph service and represent any number ot service circuits making up a system. The terminal telegraph apparatus at the ends of each of vthese Circuits is well understood in the art and accordingly is indicated schematically.

The third circuit shown, including the line Y La, serves as a pilot circuit and may be either achannel which is specially set aside for the purpose or a regular telegraph channel used Jfor this purpose during the periodsof light traiiic, 'for instance at night.

At station A I provide a` conimutator or other source of telegraph reversals, serving to transmit a regular succession ot uniform dots and spaces at the same signal frequency that is used in service. A battery is connect estrenar sisma-ias.

1926. Serialv N'o.'1521,439.`

edE between the cominutator and the ground. The .circuit is iirst lined'up7 or adjusted so thatv there is-.nofbiasi'nfy the receivedsignails. I- tlien connect the source of? reversals at station .A and continue the transmission of the telegraph reversals over an extended period ot time.

At' station' Ba receiving relay is actuated .in-.response to the' malriiigfan'd breakingof the circuit at 'stationA,-a`nd connects pfositive andnegative battery alternately to the localflcircuit shown. Thisci'rcuit includes a device arranged to follow to ysome extent theindividual received impulsesl and to produce an integrated indication of either positive or negative bias. A suitable device for this purpose is a meter (which may be a recording voltmeter or a ameter) which is so adjusted that it tends to produce an averaged reading4 of the amount by which the positive impulses eX- ceed in duration the spacing impulses or vice versa. Associated with this meter is an alarm circuit including a bell or rother suitable annunciator and a battery. Contacts are sopositioned that when the bias,

either positive or negative, exceeds a predetermined amount, the indicating arm of the meter will close the .circuit through the alarm bell and the battery. The result, of course, lis the sounding of an alarm through the operation of the belland the calling ot an attendant.

It will be understood that not only excessive bias but also any serious fortuitous distortion affecting the pilot circuit will cause the meter to actuate the alarm annunciator.

Since, as stated above, tlie other circuits of the system, for instance, with reference to the drawing, those including the lines L1 and L2,are affected similarly to the special or pilot circuit, the alarm given in connection with the one circuit serves to indicate the serious instability of the carrier system.

It is to be understood that my invention as claimed below is applicable to many kinds of telegraph systems in. addition to the simple system shown in the drawing for the purpose of illustration.

lVhat is claimed is:

l. In a telegraph system including a plul `rality of transmission circuits, the method of causing an automatic announcement of the instability ot the circuits, which consists in transmitting reversals over one circuit of recording milli-y iio the system continuously, causing the received signals to set up alternate positive and negative impulses, and causing an alarm to be given in response to either positive or nega.

t-ive bias in said impulses in excess of a predetermined amount.

2. In a telegraph system including a plurality of transmission circuits, means at one end of one circuit for continuously and regularly making and breaking the circuit, means at the other end of the circuit `for producing positive and negative impulses in response to said making and breaking of the circuit, and means associated therewith for causing an alarm to be given' in response to a bias in said impulses in excess of a predetermined amoun y l y 3. A telegraph system including a plurality of transmission circuits and apilot circuit, said pilot circuit comprising means at one end thereof forv continuously and regu- 'larly making r and breaking the circuit,

`tive and negative current impulses. in recausing an alarmto be given in response to a biasin said impulses in excess of a predetermined amount'.

4. In a telegraph system, a circuit comprising at one end thereof a battery and means for continuously and'regularly making and breaking the circuit, and at the other end thereof means for producing posispense to the making and breaking of the circuit, an alarm annunciator, and means for operating said annunciator in response to a bias insaid positive and negative impulses in excess of a predetermined amount- In testimony whereof, I havesigned my name to this specification this 8th day` of l July, 1926.

MACLEAN KIRKWOOD. 

